Question

Bacterio-chlorophyll a is represented as
A) \[{C_{55}}{H_{74}}{O_6}{N_4}Mg\]
B) \[{C_{55}}{H_{70}}{O_6}{N_4}Mg\]
C) \[{C_{55}}{H_{72}}{O_5}{N_4}Mg\]
D) \[{C_{35}}{H_{32}}{O_5}{N_4}Mg\]

Answer 1

Hint:Bacterio-chlorophyll (BChI) is the photosynthetic pigments which were discovered by C.B. van Niel. They occur in various phototrophic bacteria.

 Complete answer:

Pigment	Bacterial group
Bacteriochlorophyll a	Green sulfur bacteria, purple bacteria, helicobacter,chloroflexi, chloracidobacterium thermophilum.
Molecular formula	\[{C_{55}}{H_{74}}{O_6}{N_4}Mg\]
Molecular weight	\[911\,g/mol\]

>Bacteriochlorophylls a, b, and g are the bacteriochlorins macrocycle ring containing two reduced pyrrole rings.
>Bacteriochlorophylls c, d, e and f are chlorins whose molecules have a chlorine macrocycle ring and one reduced pyrrole ring.
>Bacteriochlorophylls c to f are closely related homologs and contain different alkyl groups and are attached to pyrrole rings.
>Bacteriochlorophylls g contains vinyl groups.
>Chlorophyllide andChlorophyllide b are precursors of chlorophyll a and chlorophyll b. Their propionic acid groups are converted by chlorophyll synthase enzyme to phytyl esters.
>Chlorophyll Idea is also used as an intermediate in the biosynthesis of bacteriochlorophyll.
>In the biosynthesis, the first step is reduction of the pyrrole ring (18-electron aromatic system) of various bacteriochlorophylls.
>This reaction is carried out by enzyme chlorophyllide, a reductase.
>Chlorophyllide\[a + 2\]reduced ferredoxin \[ + ATP + {H_2}0 + 2{H^ + }\]→ 3-deacetyl 3- vinyl bacteriochlorophyll ide\[a + 2\]oxidized ferredoxin + ADP + phosphate
>In the next steps the vinyl group first converts into 1-hydroxyethyl group and then into acetyl group of bacteria chlorophyllide a. This is catalyzed by bacteriochlorophyll ide, a dehydrogenase.

The correct answer is \[{C_{55}}{H_{74}}{O_6}{N_4}Mg\].

Note:Those organisms that consist of bacteriochlorophyll conduct photosynthesis for their energy requirement but they don’t produce oxygen as a side product.